A scheme has been proposed in which an access point has a plurality of antennas whose directivities are controlled for each terminal such that an RSSI (Received Signal Strength Indicator) in transmission to and reception from the terminal is improved. In this proposal, a characteristic for each combination of the directivities of the plural antennas is held as a list for each terminal. The list is obtained by performing a sounding of a channel during an unoccupied time. The antenna is controlled on the basis of this list. However, performing the sounding for each combination causes an overhead to increase.
On the other hand, a scheme has been proposed in which the antenna control period and an ordinary period are repeated and the directivity of the antenna is updated during the antenna control period.